Messages sent to followers are received in Notifications list even if Message Stream toggles are OFF

STEPS TO REPRODUCE

1. Login as Admin
2. Enable Message Stream from Administration
3. Create an user (e.g. U1)
4. Login with U1
5. Go to User Index, click on Admin's profile and click on "Not following" button to start following him
6. Login with Admin
7. Go to its own user's profile
8. Under Send message write a message and select Visible to 'Followers'
9. Click Share
10. Login with U1 and observe the notifications list

EXPECTED RESULTS

The message received by U1 is displayed only in Dashboard Activity Stream, not in Notifications list, since all Message Stream toggles (Notifications menu and Email) are OFF (thus including 'Message sent by someone you are following' sub-toggle).

ACTUAL RESULTS

The message is received in Notifications list, although the Message Stream toggles are OFF.

If the message is received by U1 from an user which is not followed, the message is displayed only on Dashboard Activity Stream.